battery troubleshooting help!

Cutwater28GG

Cutwater28GG

Well-known member
Joined
Jan 14, 2016
Messages
1,996
Location
seattle
Fluid Motion Model
C-28
Non-Fluid Motion Model
Cutwater 28
Vessel Name
Living The Dream
Hi
I recently bought a cutwater 28 (2012) from the dealer here in PNW and I am having trouble with the engine battery. It was weak to start when I picked up the boat from the dealer and today when starting it failed to start. boat started fine when batteries were crossovered.

so I did a little multimeter digging...

After I started the first time with all batteries, the second time i managed to successfully start (just caught) with just engine battery - but it wasn't exactly confidence inspiring! therefore I decided to retry a start with just the engine battery with the multimeter measuring min/max voltages to see if the battery is toast.

With the engine off and shorepower unplugged. engine battery is showing 12.83volts.
using the min/max feature. cranking the engine, the battery volts drop to 9.99V and once the engine battery charger kicks in after start, the voltage increases to 14.27v

when the engine is off and back on shore power the DC panel shows 14.75v showing the shorepower charger looks to be charging ok. I don't appear to have any fuses blow on the cables (I forgot to check the voltage on the actual battery when on shorepower (that shorepower plug really stops that battery hatch from opening easily 🙂)

This is a universal AGM battery. 3 years old.

Is the battery screwed or is it something else? what else can I do to narrow down the issue?

ideas appreciated!!
Gavin
 
It is not clear to me if your multimeter accomplishes a load test. It sounds like your systems for charging are working correctly. A load test will determine the battery quality. Once charged and rested you can remove it and bring it to any of the auto stores and ask them to perform a load test. This will confirm the state of your battery's ability to hold a charge. There is a good chance it may need replacing. The next action would be to determine that nothing caused the deterioration of the battery other than possible abuse. The engine battery is fairly isolated so nothing other than engine components could have drained it. A common mistake is leaving the ignition key on. This will drain the battery. As good as AGM batteries are tolerant of abuse they will still fail if abused often enough.
 
Thanks for the input!

assuming for a second that the mulitmeter min test does show a load test. what battery volts should a battery drop to when cranking?
 
I can't answer that, however I would think that it should not drop that low. A bit of work, but why not switch out one of the house batteries and see what readings you get.
 
The same thing happened to us on Kismet after three years plus....the engine AGM went bad. If you find this to be the case you should consider buying the Everstart 27DC flooded batteries from Walmart/Sams and replace all 4 batteries at one time, which is what we did. You'll spend around $250 for 4 batteries with your 4 as a core, instead of spending $210 for one battery. In the end you'll be able to replace all 4 batteries and save yourself money over the coarse of time. Batteries have been a big topic of conversation on Tugnuts so I'm sure others will add there thoughts.

Jim
 
From what I have read, 9.99V or less indicates a battery related problem. Have you cleaned all the battery, starter and ground connections? Corroded connections can cause the problems you are observing.

It is not clear from your post how long you have left the charger on. It takes many hours for the charger to bring the multiple batteries up to full charge. Each of your batteries has something like 100 AH capacity and the charger can only produce a maximum of 20A. Fairly quickly the battery terminal voltages reach a V which closes all the ACRs. Now the charger is “looking” at all batteries. The surface voltage achieved after a short charging interval does not indicate a significant charge. How much charging current does the charger panel show? Are you following the A down from an initial 20A to less perhaps 10A?
 
That's what I am including.

This battery/boat has been on shore power for two weeks. Id like to think that charging has occurred and its in float mode. I don't have a current reader on the power panel. Just volts. After plugging shore power back in after all this the volts jump back to 14.75 suggesting to me that charging is indeed working correctly.

Kismet crew, i assume I can't mix and match wet and agm's as the Chargers will not like it. For instance the solar charger has a switch for sealed and unsealed but it's one and all. I feel bad taking the other batteries out of service. They seem fine.
 
You should not mix battery types. If you go back and do a search you will find volumes on AGN v Flooded etc. I am a proponent of flooded and converted Kismet from AGM to flooded. AGM has it's merits, but with the possibilities of ruining them through inadvertent abuse, in my opinion, low cost flooded trumps AGM.
 
Mike's many musings on batteries on this site had me switch to flooded as well. It was a pleasure last summer while on the hook to have "freshies" that lasted so much longer. Adding the switch to parallel the house and thruster made it that much nicer.

On my Trojan AGM battery that came with the boat I started getting weak starts after the batteries were four years old. I got the message and switched out all of them for flooded.

I don't know about other tugboats, but on start my voltage dips momentarily to around 10 volts on the crank, bouncing back up to whatever the alternator is putting out (14+) immediately. The key here is how well it holds its charge.

Sounds to me like you need new batteries.
 
10-4 on what Mike stated about converting me to flooded and not mixing battery types. I've been very happy with the change.

Jim F
 
Overcharging AGM batteries will make them go bad as well . sometimes the charger can overcharge it , and it will vent the electrolytes in an AGM battery and you cant refill it .
I had a battery go bad after a week on shore power charger it was set for flooded when I got the boat but didn't pay attention . I bought a new battery charger thinking that's why my battery went bad and in the instructions it said "MAKE SURE ITS SET TO AGM IF YOUR CHAGING AGM BATTERIES" or the electrolyte thing will happen.

battery was under warranty at least and was replaced.
 
ok I'm being an idiot/newbie. looking through the documentation I have a promariner charger. but cant recall seeing this on the boat (I'm away from it right now). is this in the battery locker with the ACR relays or somewhere else?
 
You guys are swinging me towards flooded. after reading what seems like hundreds of posts on batteries flyingknot and Kismet make very valid points!

first I need to double check everything before potentially throwing out good batteries due to a fault elsewhere
 
Definitely make sure you have no underlying issues before you start replacing batteries. On the financial side you can replace with flooded for all four at about $360.00 plus tax from Walmart. They also have a pretty good warranty. My research indicates that they are manufactured by Johnston Controls, a major provider of batteries to many known brands being sold under their label.
I am not familiar with the cut water layout. Usually the charger and the inverter are mounted side by side. For your year they are most likely separate units.
 
If you do make the decision to switch to flooded from AGM make sure to change your charger settings back to flooded from AGM as the same thing can happen to them as described by hughesdave123 about your AGM's.

Jim
 
Hi Folks,

I wish there was an AGM/Flooded switch on the engine alternator! At least on our Yanmar, it's nothing more that an automotive alternator with a basic voltage regulator. I have to believe it's a contributor to this AGM life problem. When we took ownership, the AGM's were pretty much shot. We're using flooded now and will continue to unless I get the urge to change to Balmar multi stage regulator.

Ken

O'Meara
2013 R27
 
Doesn't the alternator put its power through the promariner charger? or is it direct to the battery? if through the promariner it shouldn't matter if its shore power or alternator? I think the solar goes direct as it has its own specialized charging circuit

I also need to change the dip switches on the solar charger if I go flooded.

there was also an interesting thread on here talking about possible settings in the Promariner charger for a 1 or 4 hour charge after battery voltage change and this may also be why some batteries are getting shorter lifespans as there is some overcharging occurring on the AGM's. Not sure my model but I may look into switching this to 1 hour from 4.

I also find it interesting how the AGM's are a $640 option on the cutwater yet so many people here are switching back to flooded.

anything else I need to think about switching to flooded? not sure if there is room but an extra house batt might be interesting whilst I am doing this!
 
If you are changing to AGM batteries you have to make sure the alternator is properly sized to it. West Marine has a good article on it. http://www.westmarine.com/WestAdvisor/Selecting-an-Alternator

AGM batteries can accept a charging current equal to 40 to 50 percent of its available capacity while standard flooded batteries can accept charging current equal to 25 percent of its available capacity. This means that if your alternator is properly sized to your flooded batteries you may need to replace the alternator with one with a higher amp rating to charge the replacement AGM batteries. Depending on your alternator, you will also likely need to install a multi-stage external voltage regulator for AGM and gel batteries. If this wasn't done it could explain the lower lifetime of your AGM batteries.

Adding a bigger alternator can add greatly to complexity including space, belt type, pulleys and whether the engine can actually handle the new load.

As a side note, the alternator does not feed into the pro-mariner charger. It does not regulate the voltage/current in any way when using the alternator.
 
I would make sure the connections are clean and tight. A drop to 10v is normal, while cranking. As long as it gets back up to over 13v quickly when the engine is running. It should climb to 14.4v. But, that said, once a battery is over 3 years old, it will start to weaken. 5 years is probably max. Bring the battery to a Pep Boys for a load test.

One of my house batteries needs replacing, I have a 2012. I suspect the shore power. IMO, you should not leave the boat plugged in. I plug in when I have to and unplug after 24 hours. Have no proof I am right, just my gut.
 
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